In a solid state imaging device, noise and defects in a captured image may become obvious as temperature increases, or distortion may occur in a captured image due to variation of temperature. Therefore, a temperature sensor is mounted in a solid state imaging device and an image signal is corrected based on the temperature of the solid state imaging device.
Conventionally, there is an imaging element circuit and an A/D conversion circuit for an imaging element, and in addition to the imaging element circuit, there are a diode used as a temperature sensor and an A/D conversion circuit for the temperature sensor. Specifically, a circuit block related to temperature measurement is present independently of a signal processing circuit block for the imaging element, and correction is performed in a temperature correction circuit in a later stage by using stored temperature measurement data.
When a diode is used as a temperature sensor, current-voltage characteristics of the diode cannot be represented by a linear approximate equation. In other words, current and voltage are not in a proportional relationship, so measurement accuracy is insufficient when using a method of obtaining temperature from the current-voltage characteristics of the diode.